CURRENT RESEARCH PROJECTS

1. Analysis of the population biology and genetics of the Septoria pathogens M. graminicola and P. nodorum. Previous studies revealed that populations of both pathogens contain a high level of genetic variation and that rates of gene flow among populations can be high. Most of this work was performed in Bruce McDonald's lab, principally on populations from the western and southern States. Relatively little is known about populations of these pathogens in the major wheat-growing regions of the central United States. It also is not known if there is gene flow among the populations on the different market classes: hard red winter; hard red spring; and soft red winter wheats. This project has two main goals:
    
   1. Detect and quantify genetic variation for molecular markers within populations of both fungi in the major wheat-growing areas of the central United States. This information can help guide the deployment of resistance genes against populations of the pathogens on the different types of wheat.
       
   2. Perform genetic analyses of molecular markers and make preliminary genetic maps of both fungi. Genetic analyses in these fungi were not possible until 1996 when workers in Europe devised methods for making controlled crosses. Genetic analyses of these fungi are necessary to interpret the population genetic work, to estimate the number of genes involved in pathogenicity and to help devise better methods for controlling disease. A genetic map and accompanying markers would be extremely useful to Septoria workers worldwide.
       
2. Phylogenetic analyses of hosts and pathogens to study pathogen speciation mechanisms and identify plant genes for "non-host" resistance. The goal of this project is to use phylogenetic analyses of related fungi to identify genes in the pathogens that may be involved in pathogenicity, virulence, and host specificity, and similar analyses of plants to identify genes that may be involved in non-host resistance. This type of resistance will be more difficult to work with but may be more permanent than resistance from wheat. Although the probability for success is lower, this type of research could have big payoffs.
    
3. Identification, quantification and genetic tagging of genes for resistance in wheat and its relatives.

The goal of this project is to determine the number and chromosomal positions of genes for resistance to Septoria diseases in wheat for marker-assisted selection of resistance in a breeding program. The long-term goal eventually is to clone the resistance genes to facilitate their transfer into wheat breeding lines. Breeding for increased resistance is complicated by the need for testing at each step with the pathogen. Molecular markers linked to resistance genes could reduce the amount of testing required and significantly speed up the breeding process.

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